Fiber synergy in multi-scale fiber-reinforced cementitious composites

A multi-scale fiber blend containing steel fibers, polyvinyl alcohol fibers and calcium carbonate (CaCO3) whiskers was designed to increase the multi-scale cracking resistance for cementitious composites. This multi-scale fiber-reinforced composite was tested for fiber synergy in compressive behavior and flexural performance. The results indicated that the multi-scale fiber improves not only the softening branch of the compressive stress–strain curve and the strain capacity at ultimate stress but also the compressive toughness, achieving a ductile fracture mode during compression. The flexural strength and toughness are significantly enhanced, which is also reflected in the deflection hardening behavior and multiple cracking performance. This suggests that there is an obvious positive fiber synergy in multi-scale fiber-reinforced cementitious composites and the multi-scale fiber can effectively interact with the multi-scale cracking process of cementitious composites. Moreover, it seems possible that steel fibers and polyvinyl alcohol fibers can be partly replaced with CaCO3 whiskers, thus the production cost of fiber-reinforced cement-based composites can be decreased.